Gianfranco Zola, whose Watford side include loan players from Pozzo family clubs and sit third in the Championship. Photograph: Richard Saker for the Observer

In a bitingly cold, otherwise empty Vicarage Road this week on Wednesday, Gianfranco Zola, former Chelsea, Napoli and Italy playing legend turned Watford manager, watched with hands clasped behind his back as his eclectic squad of nationalities skipped through a nine-a-side training joust. The goals were squeezed into less than half the pitch, but the players were relishing the game, exhibiting an intricacy of skills.

Matej Vydra, the 20-year-old striker who has scored 20 times in Watford's eye-catching ascent to third place in the Championship, was away on international duty with the Czech Republic, but several of his seven fellow loan players from the Italian club Udinese were in the session. Joel Ekstrand, the Swedish central defender, was passing the ball unruffled; Fernando Forestieri, the Argentinian forward whose loan from Udinese was converted to a permanent signing in January, prowled constantly for a goal past Jack Bonham, the 19-year-old Watford academy graduate. Geoffrey Mujangi Bia, on loan from Standard Liège, crossed high and looping, and as the ball came down, Alex Geijo, another Udinese loanee, smacked a clean left-foot volley meatily into the net.

Sudden arrivals after Watford were bought in June last year by the Pozzo family – the Italians who own Udinese, and the Spanish club Granada, from whom two more loan players were imported – these loan stars have played Zola into sight of a remarkable promotion to the Premier League. However, Watford's rise this season has attracted insistent criticism around the Football League.

Watford's critics argue that while they may not be breaking the rules by importing so many loan players, they are in breach of the spirit of them. Clubs are limited to just five loan players in a matchday squad of 18, a measure designed to protect clubs' identities and prevent them being swallowed up as feeders. Watford are seen as having taken advantage of a loophole, that loan players from clubs in other countries must sign until the end of a season, so are officially classed as permanent transfers. Watford under the Pozzos have brought in 14 loan players: nine from Udinese until Forestieri signed permanently; defender Daniel Pudil and midfielder Ikechi Anya from Granada, Mujangi Bia from Liège, as well as Matthew Briggs from Fulham and Chelsea's England Under-21 international defender Nathaniel Chalobah.

Fielding so many loanees has created the impression that the famous old Hornets have become a subsidiary training operation for Udinese, peopled by a temporary squad. Most outspoken has been the Crystal Palace manager, Ian Holloway, who described what is happening at Watford as "ludicrous".

The League appear to agree, and have recommended change which will be voted on at their AGM this summer – to include international loan players within the five permitted, and a maximum of four from any one club. After those proposed changes, Watford would not be able to field so many on-loan players.

Around football and among fans, there is also a worry that the time-served Watford youth system has been undermined by the club's decision to maintain it only at category three, not to upgrade to category one in football's new Elite Player Performance Plan (EPPP) system.

Watford have grown a little tired of having to defend themselves, and after training, Zola himself pointed out, legitimately and a touch wearily: "We did not break any rules."

When you go to Vicarage Road, they give an arrestingly different and more positive account of the club's future. The chief executive, Scott Duxbury, emphasises that the Italian owners, independently wealthy after selling the family company to Bosch, have owned Udinese for 27 years and made a notable success of it. From 1986, when Giampolo Pozzo bought the club, Udinese were built up gradually until they are now solidly established in Serie A. They developed a strategy, after early, lavish spending brought poor results, of investing in young players, selling them on and reinvesting – Alexis Sánchez to Barcelona for €26m last summer being the most recent outstanding example. Gino Pozzo, son of the family business's founder, Giampaolo, stated on taking over that they are interested in investing in their English club for similar measured progress, not a rapid sprint to the Premier League's crock of gold, fortified by loan deals.

"We are here for the long term," he promised. "This is not a case of a foreign owner with an injection of money looking for a quick return. We wish to establish Watford as a Premier League club … self-sufficient over time. Longevity to us is key to success. It is only over many years that success can be judged."

Pozzo pledged that they plan a similar strategy to that at Udinese, basing it, after an initial boost with loans from their other clubs, on their extensive scouting network and youth development. Duxbury argues that the decision not to run the highest EPPP category is because Watford trust their existing academy, and consider the new U21 league played by category one clubs to be a comfort zone for young players, not the finishing school the Premier League intends.

Duxbury and Pozzo have committed that when the club has settled, progress will be based on permanent signings, and Duxbury said that when the league's loan rules change this summer, they will look to sign permanently several of those imports currently on loan. English football's prominence, and the windfall millions paid to clubs winning promotion to the Premier League – much more than in Serie A where TV rights are sold by clubs individually – spurred the Pozzos to buy a club here. They contacted Gianluca Nani, now the technical director, who was at West Ham with Duxbury and Zola; Pozzo said he is considering Watford the family's main football venture, and certainly not a nursery club for Udinese. Supporting Duxbury's argument that the club are lucky to have the Pozzos is Watford's difficult recent history. "They are the benchmark of ownership in European football," Duxbury told the Observer. "They are long-term, sensible, reliable businessmen, who are involved in football not to make a profit – they invest all money back into their clubs. They are competitive; they want to win."

With the 1980s heyday under the ownership of Elton John long over, Watford struggled after their season in the Premier League of 2006-07 and suffered a traumatic year before the Pozzos took over. Then owned by Laurence Bassini, a Londoner who cited his business as property development, the club ran up a £2.6m loss in 2011-12 and sailed close to administration before the Pozzos bought Bassini out and took on the £13m debt. According to Watford's accounts, Bassini's company charged the club £242,000 in consultancy fees. The accounts also allege that Bassini's company owed the club £2m, which he denies. An independent football disciplinary commission had been investigating the Hertfordshire club, with the alleged misconduct charges arising from the handling of two financial transactions in 2011 which occurred during Bassini's tenure as owner and director – one of which related to the transfer of striker Danny Graham to Swansea in June 2011.

This week, the commission banned Bassini from involvement in football for three years after finding him guilty of "deception" and "misconduct". Watford emerged without a fine or points deduction because the misconduct, borrowing millions against future income without informing the League as required, was found to be Bassini's own work. Watford have instead received a transfer embargo of sorts which runs until 31 August and requires League approval for all signings. Bassini is appealing and says he will fight to clear his name but there was, on a grey afternoon, a palpable sense of relief around Vicarage Road.

In his little office, Zola smiled his winning smile, and said he is happy. There was a congratulations note resting on the table – from Barry Fry, on Zola's February Championship manager of the month award – and the Italian explained: "We have so many on loan because the club was bought very soon before the beginning of the season; we assembled the team at the last minute. This was the best way, to see how good they are, and if they want to stay with us."

The Italian said he is surprised by how well the team came together after losing four of the first six matches of the season, including a 5-1 defeat at Derby: "It was a very big challenge, to have so many players, 37 or 38, and so many foreign players, to mould them into a team and train them also."

Then he smiled again: "But we are working it out quite well. And we hope now for a good ending to this season. The project is good."

Pozzo has pointed out that Granada, who were also in financial trouble when the family bought the club in 2009, were similarly stocked with Udinese loans initially, but now, two promotions later and in La Liga, are buying their own players. Watford have a £9m budget for football, including wages, and Duxbury stressed he has to develop the club commercially, and attract more fans, if he is to have more money to invest in the team.

In the Premier League, contrary to some misconceptions, international loan players are classed as transfers and so permitted in match squads without limit, but Duxbury says Watford wants to sign most of the players permanently whether they go up or not.

All of this is a first for English football, and unsettling for many. But in the game's ownership landscape, which increasingly features investors from overseas with no previous connection to football, the Pozzos bring experience, proven success, and a much more coherent plan than most.